如何在Entity Framework和Mysql中使用规范函数 [英] how to use canonical functions in Entity Framework and Mysql

问题描述

我尝试使用 DbFunctions.AddMinutes（someminutes）和 EntityFunctions.AddMinutes（someminutes）但是当我执行我得到例如

FUNCTION projectName.AddMinutes不存在

我有谷歌搜索，但找不到如何执行规范功能。虽然有一个功能列表，但我又不知道他们属于哪个类
https： //msdn.microsoft.com/en-us/library/bb738563.aspx

我正在使用

1. MySql.Data.Entities 6.8.3.0


2. EntityFramework 6.0.0


3. MySql.Data 6.8。 4


4. MySql.Web 6.8.4


5. MySql（数据库）5.6.17

我的Linq查询如下

  IQueryable< OrderViewModel> orders = _dbContext.Orders 
 .OrderByDescending（x => x.ID）
 .Select（x => new OrderViewModel 
 {ID = x.ID，
 AddedOn = DbFunctions.AddMinutes（x.AddedOn，diffMinutes）.Value，
 Customer =（x.IsGuestCheckOut == true？x.CustomerEmail：x.Customer.FirstName ++ x.Customer.LastName），
 Phone = x.Phone，
 TotalAmount = x.TotalAmount，
 OrderStatus = x.OrderStatus}）; 
  

在路上一些条件和分页被应用

解决方案

其实我误解了错误它不是

FUNCTION projectName.AddMinutes不存在

但

FUNCTION databaseName。 AddMinutes不存在

我不知道是什么问题。我有不兼容的驱动程序/连接器，我不知道。

为了解决这个问题，我刚刚创建了名为AddMinutes的函数，它调用DATE_ADD（）函数内部。函数定义如下

  CREATE FUNCTION`AddMinutes`（actualDateTime datetime，minutesToAdd int）
 RETURNS datetime 
 BEGIN 
 RETURN DATE_ADD（actualDateTime，INTERVAL minutesToAdd MINUTE）; 
 END 
  

我明白这不是正确的解决方案，而是一个HACK

I want to add Timespan to DateTime in EntityFramework with MySql Database.

i have tried using DbFunctions.AddMinutes(someminutes) and EntityFunctions.AddMinutes(someminutes) but when i execute i get exception something like

FUNCTION projectName.AddMinutes does not exist

i have googled but cannot find how to execute canonical function. though there is a list of function but again i don't know which class they belong https://msdn.microsoft.com/en-us/library/bb738563.aspx

I am using

1. MySql.Data.Entities 6.8.3.0
2. EntityFramework 6.0.0
3. MySql.Data 6.8.4
4. MySql.Web 6.8.4
5. MySql (Database) 5.6.17

My Linq Query is as below

IQueryable<OrderViewModel> orders = _dbContext.Orders
                         .OrderByDescending(x => x.ID)
                         .Select(x => new OrderViewModel 
                                        { ID = x.ID,
                                          AddedOn = DbFunctions.AddMinutes(x.AddedOn, diffMinutes).Value, 
                                          Customer = (x.IsGuestCheckOut == true ? x.CustomerEmail : x.Customer.FirstName + " " + x.Customer.LastName), 
                                          Phone = x.Phone, 
                                          TotalAmount = x.TotalAmount, 
                                          OrderStatus = x.OrderStatus });

down the road some where condition and pagination is applied

解决方案

Actually i misunderstood the error it is not

FUNCTION projectName.AddMinutes does not exist

but

FUNCTION databaseName.AddMinutes does not exist

I don't know what the issue is. Do i have any non-compatible driver/connector , I don't know.

To solve this problem i just created function with name AddMinutes, it calls DATE_ADD() function internally. function definition is as below

CREATE FUNCTION `AddMinutes`(actualDateTime datetime, minutesToAdd int)
RETURNS datetime
BEGIN
    RETURN DATE_ADD(actualDateTime, INTERVAL minutesToAdd MINUTE);
END

I understand that this is not proper solution, but a HACK

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